LCDs have the advantages of portability, low power consumption, and low radiation, and have been widely used in various portable information products such as notebooks, personal digital assistants (PDAs), video cameras and the like. A conventional LCD such as a twisted nematic (TN) LCD provides a limited viewing angle of the LCD. Thus, MVA LCDs were developed to improve the viewing angle of the LCD.
Referring to FIG. 9, one such MVA liquid crystal display is shown. The liquid crystal display 1 includes a first substrate assembly (not shown), a second substrate assembly generally facing the first substrate assembly, and a liquid crystal layer (not labeled) sandwiched between the first substrate assembly and the second substrate assembly. The liquid crystal layer includes a plurality of liquid crystal molecules 131.
The first substrate assembly includes a color filter (not shown), a common electrode (not shown), and a plurality of first protrusions 119, arranged in that order. The color filter includes a plurality of red filter units (not shown), a plurality of green filter units (not shown), and a plurality of blue filter units (not shown). The first protrusions 119 each are triangular in cross-section, and are arranged along a plurality of V-shaped paths.
The second substrate assembly includes a plurality of parallel gate lines 121 that each extend parallel to a first axis, a plurality of first parallel data lines 122 that each extend parallel to a second axis orthogonal to the first axis, a plurality of parallel second data lines 124 each extending parallel to the second axis, a plurality of first thin film transistors (TFTs) 161, a plurality of second TFTs 162, a plurality of first pixel electrodes 171, a plurality of second pixel electrodes 172, and a plurality of second protrusions 129.
The first data lines 122 and the second data lines 124 are arranged alternately. Every two adjacent first data lines 122, together with every two adjacent gate lines 121, form a rectangular area, defined as a pixel region 150. Each pixel region 150 corresponds to a filter unit of the color filter. Each second data line 124 is disposed across the middle of a corresponding pixel region 150, and divides the pixel region 150 into a first sub-pixel region 151 and a second sub-pixel region 152.
In each pixel region 150, the first TFT 161 is located in the vicinity of an intersection of the first data line 122 and the gate line 121. The second TFT 162 is located in the vicinity of an intersection of the second data line 124 and the gate line 121. Gate electrodes (not labeled) of the first TFT 161 and the second TFT 162 are connected to the same gate line 121. A source electrode (not labeled) of the first TFT 161 is connected to the first data line 122. A source electrode (not labeled) of the second TFT 162 is connected to the second data line 124. The first pixel electrode 171 is located in the first sub-pixel region 151, connected with a drain electrode (not labeled) of the first TFT 161. The second pixel electrode 172 is located in the second sub-pixel region 152, connected with a drain electrode (not labeled) of the second TFT 162. The first data line 122 provides a plurality of first gray-scale voltages to the corresponding first pixel electrode 171 via the first TFT 161. The second data line 124 provides a plurality of second gray-scale voltages to the corresponding second pixel electrode 172 via the second TFT 162. The first gray-scale voltages and the second gray-scale voltages are applied thereto independently.
The second protrusions 129 each are triangular in cross-section, arranged along a plurality of V-shaped paths. The second protrusions 129 and the first protrusions 119 are arranged alternately.
Referring also to FIG. 10, a top-down view of orientations of four of the liquid crystal molecules 131, according to the first protrusions 119 and the second protrusions 129, is shown. In each frame, when a first gray-scale voltage is applied to the first pixel electrode 171, and a common voltage is applied to the common electrode, an electric field is generated therebetween. The liquid crystal molecules 131 in the first sub-pixel region 151 re-orient according to the electric field. The liquid crystal molecules 131 are guided by the protrusions 119, 129 and thereby become aligned along four different axes. Thus four domains are defined according to the protrusions 119, 129.
Similarly, in the same frame, when a second gray-scale voltage is applied to the second pixel electrode 172, and a common voltage is applied to the common electrode, an electric field is generated therebetween. The liquid crystal molecules 131 in the second sub-pixel region 152 re-orient according to the electric field. The liquid crystal molecules 131 are guided by the protrusions 119, 129 and thereby align along four different axes. Thus four domains are defined according to the protrusions 119, 129. Referring also to FIG. 11, because the voltages of the first pixel electrode 171 differ from the voltage of the second pixel electrode 172 in each frame, a tilt angle θ1 of the liquid crystal molecules 131 in the first sub-pixel region 151 differs from a tilt angle θ2 of the liquid crystal molecules 131 in the second sub-pixel region 152. Thus, a total of eight domains are defined in each pixel region 150. The liquid crystal display 1 achieves 8-domain vertical alignment.
However, each pixel region 150 requires a first data line 122 and a second data line 124 for the liquid crystal display 1 to perform the 8-domain vertical alignment. The layout of the first data line 122 and the second data line 124 is complicated, resulting in an increase of cost thereof.
It is desired to provide an improved liquid crystal display which can overcome the limitations described.